text: from django import forms
  from django.contrib.contenttypes.forms import generic_inlineformset_factory
  from django.contrib.contenttypes.models import ContentType
  from django.db import models
  from django.test import TestCase
  from django.test.utils import isolate_apps
  
  from .models import (
      Animal, ForProxyModelModel, Gecko, Mineral, ProxyRelatedModel, TaggedItem,
  )
  
  
  class CustomWidget(forms.TextInput):
      pass
  
  
  class TaggedItemForm(forms.ModelForm):
      class Meta:
          model = TaggedItem
          fields = '__all__'
          widgets = {'tag': CustomWidget}
  
  
  class GenericInlineFormsetTests(TestCase):
  
      def test_output(self):
          GenericFormSet = generic_inlineformset_factory(TaggedItem, extra=1)
          formset = GenericFormSet()
          self.assertHTMLEqual(
              ''.join(form.as_p() for form in formset.forms),
              """<p><label for="id_generic_relations-taggeditem-content_type-object_id-0-tag">
  Tag:</label> <input id="id_generic_relations-taggeditem-content_type-object_id-0-tag" type="text"
  name="generic_relations-taggeditem-content_type-object_id-0-tag" maxlength="50" /></p>
  <p><label for="id_generic_relations-taggeditem-content_type-object_id-0-DELETE">Delete:</label>
  <input type="checkbox" name="generic_relations-taggeditem-content_type-object_id-0-DELETE"
  id="id_generic_relations-taggeditem-content_type-object_id-0-DELETE" />
  <input type="hidden" name="generic_relations-taggeditem-content_type-object_id-0-id"
  id="id_generic_relations-taggeditem-content_type-object_id-0-id" /></p>"""
          )
          formset = GenericFormSet(instance=Animal())
          self.assertHTMLEqual(
              ''.join(form.as_p() for form in formset.forms),
              """<p><label for="id_generic_relations-taggeditem-content_type-object_id-0-tag">
  Tag:</label> <input id="id_generic_relations-taggeditem-content_type-object_id-0-tag"
  type="text" name="generic_relations-taggeditem-content_type-object_id-0-tag" maxlength="50" /></p>
  <p><label for="id_generic_relations-taggeditem-content_type-object_id-0-DELETE">Delete:</label>
  <input type="checkbox" name="generic_relations-taggeditem-content_type-object_id-0-DELETE"
  id="id_generic_relations-taggeditem-content_type-object_id-0-DELETE" /><input type="hidden"
  name="generic_relations-taggeditem-content_type-object_id-0-id"
  id="id_generic_relations-taggeditem-content_type-object_id-0-id" /></p>"""
          )
          platypus = Animal.objects.create(
              common_name='Platypus', latin_name='Ornithorhynchus anatinus',
          )
          platypus.tags.create(tag='shiny')
          GenericFormSet = generic_inlineformset_factory(TaggedItem, extra=1)
          formset = GenericFormSet(instance=platypus)
          tagged_item_id = TaggedItem.objects.get(tag='shiny', object_id=platypus.id).id
          self.assertHTMLEqual(
              ''.join(form.as_p() for form in formset.forms),
              """<p><label for="id_generic_relations-taggeditem-content_type-object_id-0-tag">Tag:</label>
  <input id="id_generic_relations-taggeditem-content_type-object_id-0-tag" type="text"
  name="generic_relations-taggeditem-content_type-object_id-0-tag" value="shiny" maxlength="50" /></p>
  <p><label for="id_generic_relations-taggeditem-content_type-object_id-0-DELETE">Delete:</label>
  <input type="checkbox" name="generic_relations-taggeditem-content_type-object_id-0-DELETE"
  id="id_generic_relations-taggeditem-content_type-object_id-0-DELETE" />
  <input type="hidden" name="generic_relations-taggeditem-content_type-object_id-0-id"
  value="%s" id="id_generic_relations-taggeditem-content_type-object_id-0-id" /></p>
  <p><label for="id_generic_relations-taggeditem-content_type-object_id-1-tag">Tag:</label>
  <input id="id_generic_relations-taggeditem-content_type-object_id-1-tag" type="text"
  name="generic_relations-taggeditem-content_type-object_id-1-tag" maxlength="50" /></p>
  <p><label for="id_generic_relations-taggeditem-content_type-object_id-1-DELETE">Delete:</label>
  <input type="checkbox" name="generic_relations-taggeditem-content_type-object_id-1-DELETE"
  id="id_generic_relations-taggeditem-content_type-object_id-1-DELETE" />
  <input type="hidden" name="generic_relations-taggeditem-content_type-object_id-1-id"
  id="id_generic_relations-taggeditem-content_type-object_id-1-id" /></p>""" % tagged_item_id
          )
          lion = Animal.objects.create(common_name='Lion', latin_name='Panthera leo')
          formset = GenericFormSet(instance=lion, prefix='x')
          self.assertHTMLEqual(
              ''.join(form.as_p() for form in formset.forms),
              """<p><label for="id_x-0-tag">Tag:</label>
  <input id="id_x-0-tag" type="text" name="x-0-tag" maxlength="50" /></p>
  <p><label for="id_x-0-DELETE">Delete:</label> <input type="checkbox" name="x-0-DELETE" id="id_x-0-DELETE" />
  <input type="hidden" name="x-0-id" id="id_x-0-id" /></p>"""
          )
  
      def test_options(self):
          TaggedItemFormSet = generic_inlineformset_factory(
              TaggedItem,
              can_delete=False,
              exclude=['tag'],
              extra=3,
          )
          platypus = Animal.objects.create(common_name='Platypus', latin_name='Ornithorhynchus anatinus')
          harmless = platypus.tags.create(tag='harmless')
          mammal = platypus.tags.create(tag='mammal')
          # Works without a queryset.
          formset = TaggedItemFormSet(instance=platypus)
          self.assertEqual(len(formset.forms), 5)
          self.assertHTMLEqual(
              formset.forms[0].as_p(),
              '<input type="hidden" name="generic_relations-taggeditem-content_type-object_id-0-id" value="%s" '
              'id="id_generic_relations-taggeditem-content_type-object_id-0-id" />' % harmless.pk
          )
          self.assertEqual(formset.forms[0].instance, harmless)
          self.assertEqual(formset.forms[1].instance, mammal)
          self.assertIsNone(formset.forms[2].instance.pk)
          # A queryset can be used to alter display ordering.
          formset = TaggedItemFormSet(instance=platypus, queryset=TaggedItem.objects.order_by('-tag'))
          self.assertEqual(len(formset.forms), 5)
          self.assertEqual(formset.forms[0].instance, mammal)
          self.assertEqual(formset.forms[1].instance, harmless)
          self.assertIsNone(formset.forms[2].instance.pk)
          # A queryset that omits items.
          formset = TaggedItemFormSet(instance=platypus, queryset=TaggedItem.objects.filter(tag__startswith='harm'))
          self.assertEqual(len(formset.forms), 4)
          self.assertEqual(formset.forms[0].instance, harmless)
          self.assertIsNone(formset.forms[1].instance.pk)
  
      def test_get_queryset_ordering(self):
          """
          BaseGenericInlineFormSet.get_queryset() adds default ordering, if
          needed.
          """
          inline_formset = generic_inlineformset_factory(TaggedItem, exclude=('tag',))
          formset = inline_formset(instance=Gecko.objects.create())
          self.assertIs(formset.get_queryset().ordered, True)
  
      def test_initial(self):
          quartz = Mineral.objects.create(name='Quartz', hardness=7)
          GenericFormSet = generic_inlineformset_factory(TaggedItem, extra=1)
          ctype = ContentType.objects.get_for_model(quartz)
          initial_data = [{
              'tag': 'lizard',
              'content_type': ctype.pk,
              'object_id': quartz.pk,
          }]
          formset = GenericFormSet(initial=initial_data)
          self.assertEqual(formset.forms[0].initial, initial_data[0])
  
      def test_meta_widgets(self):
          """TaggedItemForm has a widget defined in Meta."""
          Formset = generic_inlineformset_factory(TaggedItem, TaggedItemForm)
          form = Formset().forms[0]
          self.assertIsInstance(form['tag'].field.widget, CustomWidget)
  
      @isolate_apps('generic_relations')
      def test_incorrect_content_type(self):
          class BadModel(models.Model):
              content_type = models.PositiveIntegerField()
  
          msg = "fk_name 'generic_relations.BadModel.content_type' is not a ForeignKey to ContentType"
          with self.assertRaisesMessage(Exception, msg):
              generic_inlineformset_factory(BadModel, TaggedItemForm)
  
      def test_save_new_uses_form_save(self):
          class SaveTestForm(forms.ModelForm):
              def save(self, *args, **kwargs):
                  self.instance.saved_by = 'custom method'
                  return super().save(*args, **kwargs)
  
          Formset = generic_inlineformset_factory(ForProxyModelModel, fields='__all__', form=SaveTestForm)
          instance = ProxyRelatedModel.objects.create()
          data = {
              'form-TOTAL_FORMS': '1',
              'form-INITIAL_FORMS': '0',
              'form-MAX_NUM_FORMS': '',
              'form-0-title': 'foo',
          }
          formset = Formset(data, instance=instance, prefix='form')
          self.assertTrue(formset.is_valid())
          new_obj = formset.save()[0]
          self.assertEqual(new_obj.saved_by, 'custom method')
  
      def test_save_new_for_proxy(self):
          Formset = generic_inlineformset_factory(ForProxyModelModel, fields='__all__', for_concrete_model=False)
          instance = ProxyRelatedModel.objects.create()
          data = {
              'form-TOTAL_FORMS': '1',
              'form-INITIAL_FORMS': '0',
              'form-MAX_NUM_FORMS': '',
              'form-0-title': 'foo',
          }
          formset = Formset(data, instance=instance, prefix='form')
          self.assertTrue(formset.is_valid())
          new_obj, = formset.save()
          self.assertEqual(new_obj.obj, instance)
  
      def test_save_new_for_concrete(self):
          Formset = generic_inlineformset_factory(ForProxyModelModel, fields='__all__', for_concrete_model=True)
          instance = ProxyRelatedModel.objects.create()
          data = {
              'form-TOTAL_FORMS': '1',
              'form-INITIAL_FORMS': '0',
              'form-MAX_NUM_FORMS': '',
              'form-0-title': 'foo',
          }
          formset = Formset(data, instance=instance, prefix='form')
          self.assertTrue(formset.is_valid())
          new_obj, = formset.save()
          self.assertNotIsInstance(new_obj.obj, ProxyRelatedModel)
  
      def test_initial_count(self):
          GenericFormSet = generic_inlineformset_factory(TaggedItem)
          data = {
              'form-TOTAL_FORMS': '3',
              'form-INITIAL_FORMS': '3',
              'form-MAX_NUM_FORMS': '',
          }
          formset = GenericFormSet(data=data, prefix='form')
          self.assertEqual(formset.initial_form_count(), 3)
          formset = GenericFormSet(data=data, prefix='form', save_as_new=True)
          self.assertEqual(formset.initial_form_count(), 0)
  
      def test_save_as_new(self):
          """
          The save_as_new parameter creates new items that are associated with
          the object.
          """
          lion = Animal.objects.create(common_name='Lion', latin_name='Panthera leo')
          yellow = lion.tags.create(tag='yellow')
          hairy = lion.tags.create(tag='hairy')
          GenericFormSet = generic_inlineformset_factory(TaggedItem)
          data = {
              'form-TOTAL_FORMS': '3',
              'form-INITIAL_FORMS': '2',
              'form-MAX_NUM_FORMS': '',
              'form-0-id': str(yellow.pk),
              'form-0-tag': 'hunts',
              'form-1-id': str(hairy.pk),
              'form-1-tag': 'roars',
          }
          formset = GenericFormSet(data, instance=lion, prefix='form', save_as_new=True)
          self.assertTrue(formset.is_valid())
          tags = formset.save()
          self.assertEqual([tag.tag for tag in tags], ['hunts', 'roars'])
          hunts, roars = tags
          self.assertSequenceEqual(lion.tags.order_by('tag'), [hairy, hunts, roars, yellow])
  